Highly selective Backlog Qs for JEE MainPhysicsThermal Properties of Matter
Two metal rods 1 and 2 of same lengths have same temperature difference between their ends. Their thermal conductivities are K₁ and K₂ and crosssectional areas A₁ and A₂ respectively. If the rate of heat conduction in 1 is four times that in 2 , then:
Options
- AK₁ A₁=4 K₂ A₂
- BK₁ A₁=2 K₂ A₂
- C4 K₁ A₁=K₂ A₂
- DK₁ A₁=K₂ A₂
Correct answer
A. K₁ A₁=4 K₂ A₂
Step-by-step solution
Let L= length of each rod Temperature difference = T Rate of flow of rod (i) is H₁= K₁ A₁ T L and Rate of flow of rod (2) is H₂= K₂ A₂ T L from the equation array rlrl H₁ & =4 H₂ & K₁ A₁ T L & =4 K₂ A₂ T L & K₁ A₁ & =4 K₂ A₂ array